"He was strangled by agents of [Rwandan President Paul] Kagame." Ntwali said.

Karegeya was killed at the Michelangelo Towers, an upmarket hotel in the Johannesburg suburb of Sandton. It was not immediately clear if he was killed on Tuesday night or on Wednesday.

Karegeya, in his early fifties, was for a long time very close to Kagame.
He served as head of external intelligence for around a decade before being demoted to army spokesperson and was later arrested and jailed.

He was stripped of his rank of colonel in 2006 and fled into exile the following year.

Another prominent Rwandan dissident in South Africa, Faustin Kayumba Nyamwasa, survived two assassination attempts in June 2010.

The RNC statement said investigations had found "overwhelming evidence of the involvement of Rwandan intelligence operatives in those attempts". Rwanda has vehemently denied involvement in the attacks.

Karegeya and Nyamwasa are both prominent figures in the opposition party, despite not holding specific posts.